Enhance transfer estimateFee API with an "include fee" mode

[JonRay15]

Issue

When users make a transfer now Console is calling estimateFee API to get this estimate.

The slight UX issue with this is that you cant set your transfer to "include fee" anymore, and therefore it isnt very clean or intuitive when you just want to "Use Max" because we dont actually know the max. Users just have to sort of trial and error a large amount that hopefully leaves enough balance over to cover the fee.

Request

Ideally the estimateFee API would have an input to allow you request "includeFee" mode, whereby if the user wanted to pay a total of say 100 VEGA the API would return the transfer size + fee that will total that amount.

This would then also support a "Use max" type function in the front end.

eg.

Normal Mode
FE submits amount X >> API returns the fee incurred Y

Include Fee mode
FE submits amount X >> API returns the fee incurred Y and the amount to transfer Z where X = Y + Z